Number: AV20-157
Date: 21 May 2020
On 19 May 2020 ISC released a security bulletin to address two high severity vulnerabilities affecting version 9 of their BIND DNS product. The first vulnerability only affects recursive resolvers and could allow a remote actor to use vulnerable systems as part of an amplification distributed denial of service (DDoS) attack. The second vulnerability affects both recursive resolvers and authoritative servers and could allow a remote actor to trigger an assertion error on vulnerable systems, causing them to operate in an inconsistent state and deny service to clients.
ISC has released versions 9.16.3, 9.14.12 and 9.11.19 of BIND 9 to resolve these issues.
The Cyber Centre encourages users and administrators to review the following web link, follow recommended mitigations and apply the necessary updates:
https://www.isc.org/blogs/bind9-vulnerabilities-2020-05/
Current versions of BIND are available for downloaded at the following link:
Note to Readers
The Canadian Centre for Cyber Security (Cyber Centre) operates as part of the Communications Security Establishment. We are Canada’s national authority on cyber security and we lead the government’s response to cyber security events. As Canada's national computer security incident response team, the Cyber Centre works in close collaboration with government departments, critical infrastructure, Canadian businesses and international partners to prepare for, respond to, mitigate, and recover from cyber events. We do this by providing authoritative advice and support, and coordinating information sharing and incident response. The Cyber Centre is outward-facing, welcoming partnerships that help build a stronger, more resilient cyber space in Canada.